When a person sustains a lower extremity injury, such as a hip injury, recovery from the injury often requires physical therapy. An aspect of physical therapy involves applying proper amounts of force through the injured limb. If force is applied in excess, re-injury of the limb is possible; however, if the injured limb is not subjected to adequate force, recovery time is extended. In a physical therapy session, the patient works with a trained technician or physician to ensure proper forces are being transmitted through the injured limb.
This is done through various measures and the use of various tools including, but not limited to: weight bearing harnesses, force plates embedded in the ground, and the mathematical analyses of images, information, and other feedback provided by the measures. For example, weight bearing harnesses apply upward forces on the torso or pelvis of the patient thereby limiting or minimizing forces through the legs. Based on relevant analysis and the application of different upward forces through the harness, the technician or physician can carefully and accurately distribute the proper amount of weight through the patient's injured limb. Similarly, force plates embedded in the ground provide live feedback to the technician of the amount of weight applied by the patient in each leg.
Both of these methods require training the patient to learn and comprehend by muscle memory the correct amount of force to apply through the leg. However, outside of physical therapy sessions, the patient lacks feedback or instrumentation to determine if the correct amount of weight is being applied through each leg or injured limb. In the absence of a feedback instrument, the patient may apply an excessive or otherwise inappropriate amount of force, which can potentially cause further problems or complications.